It's always after the fact rationalizing, never before the fact prognostication.
this is completely false. in fact, its the reason that i actually give some credence to mlsoft's theories. and, even though he argued with me on 'scientific theory' last weekend, his theory stands up: he's given precise information on when you should see intervention (to stem a selloff that could cascade) and where to look (intc and other stocks that get jammed by buying that appear intent not on buying for a good price, but buying to raise the price). that's predictive enought for me. in fact, up until march, there were other verifiable criteria as well: after the nikkei closed they'd jam up the dollar, push down gold and jam the futures; that would be followed by a gap up day that continued to trend up.
anyway, the question really gets turned around, i think. the market does believe in a 'greenspan put'. at this point in time, how else could he implement it? he can't really credibly do it through lowering rates or otherwise through the bond market, since he has no credibility there. and the market behavior that we're seeing is consistent with believing that there is such a put: buy an sufficiently broad basket of crap at any price, because there's a floor there.
to me,though: if there were large scale manipulation, i'd think it more likely that it was hatched out of the white house. the fed would be helpless to do anything but support it (that put again) since the alternative would be disasterous.